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As the Swedish chef would say “Hoobee scoobee floodoos.” Truth be told I’m not the most technical of gun guys. I know just enough about all the scientific type stuff to know that I need to read Nick’s posts as carefully as possible, making sure that there’s nothing to distract me from his information like . . . anything. Hey, where’s my coffee? How about you? How much metallurgy, aerodynamics, chemistry and technical info do you know about guns? [courtesy]

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  1. A good example:

    When asking about what the tolerence is for the max load my casull gun that relates to grain count per bullet my gun dealer ( who sold me the gun ) just grabbed a box of hornady 300 grain hollow points and said these are the ones you want.

    I found out later by exhaustive searching the manufuctures website that my gun was rated for 300 grain bullets as the most powerful load that can be used and the numbers to back it up.

    At my next trip to the same gun dealer I asked how he kept all that info straight in his head what with all the different makes, calibers, metals, ect. ect. ect. and he told me he just assumed the 300 grain bullets would work because that was the ones he had in stock at the time and they were meant for a casull gun!

    I tell everyone who wants to buy those “hot” rounds for their home defense to make sure that their gun is rated to handle those super-duper-rounds before they go capping them off in the middle of a crisis just to watch your gun explode in your hand because those +++P rounds just blew your barrel apart!

    • I have repeatedly told a local gun shop that 7.62 x 25 Tokarev is not the same as 7.63 x 25 Mauser, but the sign stays the same. Ah well, the rounds are cheap, and I know what I’m buying. Caveat emptor.

  2. I love shows such as How It’s Made, NatGeo Megafactories, NatGeo Ultimate Factories, NatGeo Megastructures, and a list from the BBC that’s too long to go into, but almost universally think they don’t give me as much technical information as I’d like to have.

    So the answer to “How much do you know?” is “Not enough.”

    • Same here often when I guy a firearm I try to find some kind of armors dvd or what not on the firearm. I like to know the details of how things work not just my firearms.

    • They rarely do give solid technical information. I’ve seen episodes of “How Stuff Works” (I think that was the name of it) and they have a tendency to over-simplify… even to the point of making the information incorrect sometimes. (in this case of making the information incorrect, it was a record turntable and the way the magnetic cartridge worked.)

      Just be aware shows like that won’t ever provide in-depth information, and sometimes they’ll dumb-down an explanation to the point of getting it wrong.

      A smart person will always know there is more to learn. A dummy thinks they know everything.

      Now, how techincal am I? Not nearly enough, yet. I’m learning whenever I can though…. and hopefully the correct stuff. (Check sources, seek others sources for verification.)

  3. I know that the bullet comes out of the end of that round thingy and that Glock’s are ugly but good, kinda like old Volvos. What else is there?

    • Oh, and I also know that if we don’t get the edit button back soon I’m going to throw my %&$^_)* computer through my %&$^_)* window.

    • I believe guns with short barrells are for shooting things that are close; guns with long barrells are for shooting things that are far away!

  4. I’m too technical. I love learning about interior and exterior ballistics, materials, manufacturing techniques, and the history of firearms design. I do it for my own enjoyment and I keep it to myself, because no one else cares. When my friends ask me a firearms related question, I’ll ask them if they want the short answer or the long answer. They rarely want the long answer!

    • Know exactly where your at. I’ve a bad rep at work about being a too quiet introvert….until the shooting thing comes up. Then they complain that they can’t shut me up! 😉

  5. If you’re seriously into guns, you almost have to be. Otherwise, what’s the point? For self defense, you only need one or two, and know enough to select a little ammo for them. If you’re collecting, or competing, or customizing, or just shooting for extreme accuracy on your own, you’re going to have to learn some technical details just to realize your goals.

  6. On semi-auto pistols (which I have two of), I’m quite knowledgeable and trying to learn a little more. On revolvers, rifles, and shotguns (which I have none of), I’m not very knowledgeable, but I know a lot more than the average guy out there.

    On the politics of gun rights, I’m very knowledgeable. I can’t compare to Bruce Kraft, but I can tear apart an anti-gun editorial everytime.

  7. Lets see? My Dad was raised as a dirt poor Hillbilly in East Tennessee. He educated himself off the farm, started in the post war Manhatten Project after doing his time behind a Garand in Europe, and retired from the Shuttle Program at Merritt Island. He taught me the joy of a good squirrel hunt and the fascination of the physics behind space flight. To make a long story short, when I decided that I could finally afford to build a wildcat varmit rifle of my own design, I spent 18 months just doing the research. The project worked out perfectly, but the study was probably the best part. Yea, I might not have the knowledge, but I am definitely technical.

  8. @ RF – I think this would be a great new thread for here. Overly technical gun knowledge. It would really be quite interesting. I’m sure there are plenty of people here with enough knowledge to share.

  9. OK, let’s get to the real data on the subject of the video.

    The most important difference(s) between the .223 Rem and 5.56 NATO chambers is found in the following table, presented with Andrew’s other test results:

    Look at variables “N” (freebore length) and “R” (throat angle).

    In particular, compare the “PTG” numbers between PTG .223 Rem Match, PTG .223 Rem and PTG 5.56 NATO, then between the Clymer .223 Rem and Clymber 5.56 NATO. BTW, “PTG” stands for “Pacific Tool and Gauge,” a highly reputable supplier of chamber reamers, gages and tools for us gunsmiths.

    Let’s back up a minute, because we have so many non-technical people on TTAG. “Freebore” in a chamber is the distance that the bullet can jump out of the case before the bullet contacts the lands of the rifling in the barrel.

    The throat angle should be pretty obvious – it is the chamfer angle of the throat in the chamber.

    OK, what *can* happen with differences between chamber dimensions between the .223 and the 5.56 is this: If a loaded round (of presumably 5.56 NATO) that is assuming the existence of the longer freebore of the NATO chamber is put into a .223 Rem chamber, it is possible with heavier weight or VLD bullets that the bullet could be in contact with the lands of the rifling upon being chambers.

    This, as any experienced reloader can tell you, can be Not A Good Thing[tm]. When the bullet doesn’t have room to “jump” upon ignition, the pressure in the cartridge can spike shortly after ignition. Now, some reloaders deliberately load their ammo to be in contact with the lands when the action is closed (typically on bolt guns), but these people usually know what they’re doing and they compensate for the expected pressure spike by reducing their powder load or using different powders. Don’t think that because some benchrest guys are loading to contact the lands for accuracy that you should too, unless you listen to everything the bench guys are telling you about their loading.

    How high can the pressure spike? We don’t know without tests. It will vary by powder formulation, ambient temperature, rifling twist rate, etc.

    While there aren’t issues with M855 or XM193 5.56 ammo in .223 chambers, this doesn’t predict that all NATO loads in the future will not use the larger freebore to their advantage. We already see the military pushing the limits of the 5.56 with the M262 loads, which are both pretty hot loads and they’re pushing a larger bullet (77 grains) to attempt to achieve something approaching a real rifle round as opposed to a varmint round.

    Finally, here’s a guideline as to chamber pressures: It is an accepted wisdom among gunsmiths that when someone starts pushing load pressures up to near 70,000 PSI, cartridge failure is close behind, and sometimes will have already happened on chambers with too much headspace, sloppy dimensions or modified chambers for feeding issues. Typical post-WWII centerfire rifle pressures will be in the mid-to-high 50K range, with some modern “magnum” cartridges pushing pressures to 63 to 65K PSI. Above 65K PSI, you’re using all of your safety margin, and everything had better be spot-on, every single time.

    What do I tell my customers? What my lawyer tells me to tell customers. Don’t shoot ammo not marked for the chamber in question.

  10. I’m a hobbyist and an enthusiast, so I know that I don’t know everything, but want to. I do know enough to choose the ammunition, shoot, and then clean every gun I own, and I keep learning more.

  11. I’m a (admittedly recent) competitive shooter and a mechanical engineer. The will and patience to dissect every little thing flows through my veins as easily as sh!t off of a duck’s back. So my answer to the question would be, “Enough to get myself in trouble, and I want to know more in order to avoid such.”

  12. I love the science in just about everything; shooting is no different.

    Ballistics are a fun study, and more practically, understanding how my rifle or sidearm functions mechanicaly, makes for a safer more effective shooter. Even if you don’t know all of the fancy terminology or the math behind the concepts, if you shoot, then you probably understand allot more about the science of shooting then your realize.

  13. I submitted a comment yesterday pointing out the important differences in chamber dimensions between a .223 Rem and 5.56 NATO chamber, but the TTAG software saw fit to pipe it off to /dev/null. Long story short: Look at the leade and throat angle dimensions.

    That’s the last time I bother trying to impart technical information on this blog.

  14. Just get into reloading and you’ll become an expert on all of it because you have to…

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